The charcoal record contained in lake sedimentary sequences is often used to infer past fire events. Studies to calibrate such charcoal records have been carried out in a range of mid- to high-latitude regions and relationships have been determined between size and quantity of charcoal in the sediment and proximity and spatial extent of the fires. Very little is known, however, about the relationship between fire events in savanna ecosystems and how these are represented in the charcoal record in lake sedimentary sequences. This study presents the results of a project that aimed to calibrate the micro- and macroscopic charcoal record from Kruger National Park, South Africa, with known fire events. Surface sediment samples were analysed for charcoal of different size classes and compared with data on fire proximity, area and intensity (the rate of energy released along a fire front) from fire events over the last 10 years, and the relevant source areas for micro- and macroscopic charcoal were quantified. Results indicated that (i) the Relevant Source Area of Charcoal for lakes c. 200 m diameter is between 0 and 5 km for charcoal particles >50 ∝m in length and between 10 and 15 km for charcoal particles <50 ∝m; (ii) that charcoal deposits are most likely to represent combined fire events from the preceding five years; (iii) that fire proximity, area and intensity are each significantly represented in the charcoal record, but not equally, as the signal resulting from fire intensity is stronger than that for fire proximity or area. Mathematical equations linking charcoal with fire proximity, area and intensity are presented.

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In the Kruger National Park (KNP), South Africa, ecosystem managers use a series of monitoring endpoints, known as thresholds of potential concern (TPCs), to define the upper and the lower levels of accepted variation in ecosystems. For woody vegetation, the current TPC suggests that woody cover should not drop by more than 80% of its 'highest ever' value. In this paper, we explore the utility of palaeoecological data in informing TPCs. We use calibrated fossil pollen data to explore variability in vegetation at two sites over the past 5000 years, to provide a long-term record of changes in woody vegetation cover and a context for interpreting more recent vegetation change. The fossil pollen data are calibrated using studies of modern pollen and vegetation from KNP; arboreal pollen percentage was simulated using pollen-landscape modelling software for savannah landscapes of varying woody vegetation cover, and the relationship between vegetation and pollen data was quantified using nonlinear regression. This quadratic equation was then applied to fossil pollen data in order to estimate woody vegetation cover from arboreal pollen percentages. Our results suggest that the TPCs have not been exceeded during the period represented in the pollen record, because estimated woody vegetation cover has remained above 20% of its highest ever value. By comparing the fossil pollen data with TPCs, our study demonstrates how palaeoecological data can be presented in a form that is directly relevant to management objectives.

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